The presentation begins with a discussion of how to characterize dry materials typically used in plastic compounding. Then we will discuss various feeder types: single screw, twin screw, vibratory, belt–along with hopper design and agitation techniques to ensure that the dry ingredients flow out of the feeder and into the extruder. Then finally we will focus on the principles of operation of Loss-in-Weight feeders and how these relate to optimal feeder design.